The Cohorts and Databases Core (CDC) will maintain two cohorts of patients and their associated databases and continuallyupdate and add information. In addition,the Core will maintaina database supporting tissue storage and use. The two populations of patientsare men and women with breast cancer or women at increased risk because of genetic or histologic risk factors. Tissues are those blood samples and breast specimens kept in repositories at the DFCI, B\VH or MGH. The databases are called CRIS (C'linical Research Information System), REACH (Risk EvaluationAnd Cancer History), and STIP(Specimen Tracking and Inventory Program). Men and women with breast cancer are prospcctively enteied into CRIS from the GilletteBreast Oncology Clinic at the DFCI and the AVON Breast Evaluation Center at the MGH. Women at high risk for breast cancer arc entered into REACH at the risk evaluationclinics at the DFCI and B1DMC. Data managers at the DFCI and MGH prospectively enter data into both registries. Users in the tissue banks at the DFCI, BWH and MGH use STIP for entry and inventory purposes. Reports are issued by specialized software to requesting investigatorsand down loaded to other registries. All three databases are kept on Partners HealthCareInformation Systems' central computer facilities, and available onworkstations throughout the Partners System. The Core will provide reports to SPORE investigators who have approved projects and after consultationabout data requirements. The Core is also availableto collaboratorswho are members of the DF/HCC or other investigatorson a case-by-case basis. The Core will participate in the Core Coordinating Committee and will abide by policies and procedures agreed upon by the Committee.